Exchange database dismounted due to NTFS file extent limit reached – unexpected outage
Hi everyone, We experienced a serious outage on our Exchange 2016 server recently, and I wanted to share what we found during the root cause analysis – in case it helps someone else avoid the same scenario. Summary: After digging deep, we discovered that the issue was caused by the NTFS file system hitting its internal file extent limit on the .edb file. Once this threshold was reached, the database could no longer grow, and the system dismounted the database unexpectedly. No prior warning, just service interruption. Details: The .edb was around 1.2 TB in size. This isn’t a limit on database size itself — it’s about how fragmented the file is on disk. Once NTFS couldn’t track any more extents, the database stopped working. Microsoft doesn’t publish a clear fix for this; only scattered references to similar behavior in past cases. What we did: Created a fresh, clean database. Manually moved user mailboxes into the new DB. The old database couldn't be mounted anymore, so we brought the system live without historical mail – just to maintain continuity. We're now working on extracting data from the unmounted .edb using third-party tools. Looking for thoughts: Has anyone else hit the NTFS extent wall with Exchange? How do you monitor extent growth proactively? Did switching to ReFS solve this for you long-term? Open to any input or similar experiences – appreciate it in advance. Thanks!
Dynamic Distribution Group with no Disabled Accounts
Hi I'm trying to build a few Dynamic Distribution Lists in Exchange Online and want to only include Active Users (i.e., users that are marked "Active" in Azure AD). I've tried using the UserAccountControl attribute (-eq 514 or -ne 514 - both are returning the same results, which is strange), but it still includes user accounts that are disabled. This is how my recipient filter looks like: RecipientType -eq 'UserMailbox' -and UserAccountControl -ne 514 What's the best way to achieve this in Exchange Online? Thanks Taranjeet Singh
Exchange 2010 to Microsoft 365 Migration – Recommended Approach and Tools
I’m looking for guidance on migrating Exchange 2010 (on-premises) to Microsoft 365 / Office 365. Is a direct migration from Exchange 2010 supported, or is an intermediate hop (such as upgrading Exchange or setting up a hybrid configuration) required? Additionally, could you please recommend any reliable tools that can help with this migration? I also have a few PST files that need to be migrated as part of the process. I’d appreciate insights on best practices, common challenges, and lessons learned from real-world migrations. Thanks in advance for your help.
Teams delegation permission issue with Onpremise Exchange Server
we have migrated the exchange server from 2019 to SE Environment and configure the OAuth 2.0 which is working perfectly but there is one issue that one of the user is using Shared calendar but while he create the meeting invite along with Teams meeting option then everytime it shows an error "please login into the meeting" If anyone works on this case please guide or help us. Thanks
DMARC rejection after Exchange upgrade
I'm having problems with inbound emails getting bounced as Undeliverable due to DMARC rejection. For many years I've had my email come through Fasthosts / Livemail to my own domain (qts.org.uk) with catch-all forwarding set to forward everything to my GMail account. Just recently Fasthosts have upgraded their servers to Exchange and I've started getting DMARC rejections from GMail which start Diagnostic information for administrators: Generating server: exchange2019.livemail.co.uk Total retry attempts: 1 (my gmail email address) t1-hex-xprelay.gem.livemail.co.uk Remote Server returned '550 5.7.26 Message rejected by DMARC policy by gmail.com. Please use your own email address as the sender, instead of (sender's email address). [MSG0009]' Which bounce from Fasthosts / Livemail back to my GMail address. My own domain has SPF, DMARC, and DKIM configured I've done a little digging and it appears to only affect senders from originating domains with DMARC set to reject. So either GMail has coincidentally become much more strict (possible) or Fasthosts are somehow failing to forward emails fully transparently. I have spoken to Fasthosts and logged the issue with them and was not impressed so I hope the experts here can offer a solution I can forward to them.Exchange 2019 Certificate Error
Hello guys, I plan to migrate my users on Exchange 2019, currently, i have 2 Exchange 2013 servers. As soon as i installed the exchange Server 2019, I changed all the virtual directories and i also runned the command to make sure the users doesn't connect on the new server. But now every users who uses Microsoft Outlook from the environment have a pop up that says that the certificate is not valid, and its normal because I can't apply the services SMTP and IIS on my wildcard certificate. Indeed, when i enable the services SMTP and IIS on my new certificate, it doesn't apply. I tried to enable from the ECP, it says "Are you sure you want to replace the existing certificate", when i say yes, it doesn't change anything, the smtp service is still unchecked. I also tried to stop IIS and restart IIS, restart the server but it doesn't changed anything, and I also tried to enable the services directly with the powershell command with the correct thumbprint of the wildcard certificate as it is said on the event viewer : "Enable-ExchangeCertificate -Server "EX01-2019" -Thumbprint A6BC992FDD... -Services SMTP,IMAP,IIS -Force" But it still don't work, when i check the certificate, only the service IIS is active. I had to uninstall completely the exchange server, because users were complaining about the pop up. Have anyone faced this problem before? Thank you very much for your advices guys
Keep user account but provision new empty mailbox
i did ask in another forum but thought i would ask here as it seems impossible... we are hybrid exchange. We have litigation hold and purview retention policies in place. We have a scenario where an existing user is moving to a new role and her existing mailbox needs to be dissociated from her AD account and a new clean mailbox provisioned. The original mailbox needs to stay as inactive and searchable via ediscovery. Is it possible? I have asked AI and its said: Make sure all the holds and retention policies are in place Move the AD account to a non-syncing OU and run a delta sync The mailbox should show as inactive in exchange online Then it tells me to run Set-User <UserUPN> -PermanentlyClearPreviousMailboxInfo but ONLY if the recipient type shows as MailUser or User This is where i am stuck as it is still UserMailbox. It told me to restore the cloud only object which i did. But it still shows as RecipientType = UserMailbox when i check. Its now just a cloud only account, it has no license. The mailbox is inactive but its still a UserMailbox Is what i am trying to do possible? Would now just changing the cloud only account to have a new email address be the only way to retain it and then sync back the on-prem account?
OWA “Manage Add-ins” Stuck Loading After Clicking Settings (Exchange 2019 CU15 / Exchange SE RTM)
I have an Exchange Server environment with three versions: Exchange Server 2019 CU14 Dec25SU, Exchange Server 2019 CU15 Sept25H, Exchange Server SE RTM, and Exchange Server SE RTM Dec25SU. Issue: When users click the Settings icon/button in OWA/Outlook on the web and then click Manage add-ins, the page does not redirect and remains stuck on an external loading screen. Tested environments: Exchange Server 2019 CU14 Dec25SU: Works without issues Exchange Server 2019 CU15 Sept25H, Exchange Server SE RTM, and Exchange Server SE RTM Dec25SU: Does not work on any of them Troubleshooting performed: Moved all arbitral mailboxes to a database on Exchange Server SE RTM Dec25SU (the most recent version in the forest). (No success) Migrated all servers to Exchange Server SE RTM Dec25SU. (No success) Isolated testing using the hosts file (DNS) pointing to each host individually, and all hosts have the issue. All SE RTM Dec25SU servers were installed in admin mode via Command Prompt. I also ran the two .ps1 scripts below on a test host after installing the SU: #learn.microsoft.com/en-us/troubleshoot/exchange/client-connectivity/owa-stops-working-after-update cd "C:\Program Files\Microsoft\Exchange Server\V15\Bin" .\UpdateCas.ps1 .\UpdateConfigFiles.ps1 iisreset /restart Workaround: With the user already authenticated, if I manually open the URL below in the same authenticated session, it loads normally: webapp.mydomain.com/owa/#path=/options/manageapps Does anyone know how to fix this, or if this is a bug that started with CU15 (or a later SU)?
